Straight Leg Raise Test
The Straight Leg Raise (SLR) test is a neurodynamic test. Neurodynamic tests check the mechanical movement of the neurological tissues as well as their sensitivity to mechanical stress or compression. These tests, along with relevant history and decreased range of motion, are considered by some to be the most important physical signs of disc herniation, regardless of the degree of disc injury. SLR is a neural tension test that can be used to rule in or out neural tissue involvement as a result of a space occupying lesion, often a lumbar disc herniation. It is one of the most common neurological tests of the lower limb.
The straight leg raise is a passive test. Each leg is tested individually with the normal leg being tested first. When performing the SLR test, the patient is positioned in supine without a pillow under his/her head, the hip medially rotated and adducted, and the knee extended. The clinician lifts the patient's leg by the posterior ankle while keeping the knee in a fully extended position. The clinician continues to lift the patient's leg by flexing at the hip until the patient complains of pain or tightness in the back or back of the leg.
- If symptoms are primarily back pain, it is most likely the result of a disc herniation applying pressure on the anterior theca of the spinal cord, or the pathology causing the pressure is more central. "Back pain only" patients who have a disc prolapse have smaller, more central prolapses.
- If pain is primarily in the leg, it is more likely that the pathology causing the pressure on neurological tissue(s) is more lateral.
- Disc herniations or pathology causing pressure between the two extremes are more likely to cause pain in both areas.
- Neurologic pain which is reproduced in the leg and low back between 30-70 degrees of hip flexion is suggestive of lumbar disc herniation at the L4-S1 nerve roots.
- Pain at less than 30 degrees of hip flexion might indicate acute spondyloithesis, gluteal abscess, disc protrusion or extrusion, tumor of the buttock, acute dural inflammation, a malingering patient, or the sign of the buttock.
- Pain at greater than 70 degrees of hip flexion might indicate tightness of the hamstrings, gluteus maximus, or hip capsule, or pathology of the hip or sacroiliac joints.
After the elicitation of symptoms, the examiner can slowly and carefully lower the leg until the patient no longer feels pain or tightness. Next, either the patient is asked to bring his or her chin to the chest, or the examiner may dorsiflex the patient's foot, or both actions may be done simultaneously; however, foot dorsiflexion is most commonly performed first. Both maneuvers are considered to be provocative or sensitizing tests for neurological tissue.
Pain that increases with neck flexion or foot dorsiflexion or both indicates stretching of the dura mater of the spinal cord or a lesion within the spinal cord (e.g. disc herniation, tumor, or meningitis) 
Pain that does not increase with neck flexion may indicate a lesion in the hamstring area (tight hamstrings) or in the lumbosacral or sacro-iliac joint.
- Inclusion of neck flexion in the SLR is documented as Hyndman's sign, Brudzinski's Sign, Linder's Sign, or the Soto-Hall test.
- Inclusion of ankle dorsiflexion in the SLR is documented as Lasegue's test or Bragard's test.
- Inclusion of great toe extension in the SLR (instead of ankle dorsiflexion) is documented as Sicard's Test.
Modifications to the Straight Leg Raise test can be used to stress different peripheral nerves to a greater degree; these are referred to as SLR tests with a particular nerve bias.
|HIP||Flexion and adduction||Flexion||Flexion||Flexion and medial Rotation||Flexion|
|NERVE BIAS||Sciatic Nerve and Tibial Nerve||Tibial Nerve||Sural Nerve||Common Peroneal Nerve||Nerve Root (Disc Prolapse)|
- A Cross-sectional study by Boyd and Villa (2012)  examined normal asymmetries between limbs in healthy, asymptomatic individuals during SLR testing and the relationship of various demographic characteristics. The authors concluded that Overall range of motion during SLR was related to sex, weight, BMI and activity level, which is likely reflected in the high variability documented. We can be 95% confident that inter-limb differences during SLR neurodynamic testing fall below 11 degrees in 90% of the general population of healthy individuals. In addition, inter-limb differences were not affected by demographic factors and thus may be a more valuable comparison for test interpretation.
- Rabin et al. has shown sensitivty of the SLR test to be .67
- Deville et al. found the specificity to be .26 .
- A systematic review of the Clinical utility of SLR by Scaia V, Baxter D and Cook C (2012) investigated the diagnostic accuracy of a finding of pain during the straight leg raise test for lumbar disc herniation, lumbar radiculopathy, and/or sciatica.The authors concluded that Variability in reference standard may partly explain the inconsistencies in the diagnostic accuracy findings. Further, pain that is not specific to lumbar radiculopathy, such as that associated with hamstring tightness, may also lead to false positives for the SLR; and may inflate the sensitivity of the test.
- Diagnostic Test accuracy review (Cochrane Meta analysis)  assessed the performance of tests performed during physical examination (alone or in combination) to identify radiculopathy due to lower lumbar disc herniation in patients with low-back pain and sciatica. The review included 16 cohort studies (median N = 126, range 71 to 2504) and three case control studies (38 to100 cases). Only one study was carried out in a primary care population. Most studies assessed the Straight Leg Raising (SLR) test. In surgical populations, characterized by a high prevalence of disc herniation (58% to 98%), the SLR showed high sensitivity (pooled estimate 0.92, 95% CI: 0.87 to 0.95) with widely varying specificity (0.10 to 1.00, pooled estimate 0.28, 95% CI: 0.18 to 0.40). Results of studies using imaging showed more heterogeneity and poorer sensitivity. The crossed SLR showed high specificity (pooled estimate 0.90, 95% CI: 0.85 to 0.94) with consistently low sensitivity (pooled estimate 0.28, 95% CI: 0.22 to 0.35). Combining positive test results increased the specificity of physical tests, but few studies presented data on test combinations.The authors of the meta analysis conclude that When used in isolation, current evidence indicates poor diagnostic performance of most physical tests used to identify lumbar disc herniation. However, most findings arise from surgical populations and may not apply to primary care or non-selected populations. Better performance may be obtained when tests are combined.
Recent Related Research (from Pubmed)
- David J. Magee;Orthopaedic Physical Assessment; Chapter 9-Lumbar Spine;Fifth Edition: Pg 558-564.
- Dutton, M. (2008). Orthopaedic: Examination, evaluation, and intervention (2nd ed.). New York: The McGraw-Hill Companies, Inc.
- Butler DA: Mobilisation of the nervous system, Melbourne,1991,Churchill Livingstone.
- Boyd BS, Villa PS. Normal inter-limb differences during the straight leg raise neurodynamic test: a cross sectional study. BMC Musculoskeletal Disorders. 2012;13:245. doi:10.1186/1471-2474-13-245.
- Rabin A, Gerszten PC, Karausky P, et al. The Sensitivity of the Seated Straight-Leg Raise Test Compared With the Supine Straight-Leg Raise Test in Patients Presenting With Magnetic Resonance Imaging Evidence of Lumbar Nerve Root Compression. Arch Phys Med Rehabil. 2007;(88):840-843.
- Deville WL, van der Windt DA, Dzaferagic A, et al. The test of Lasegue: systematic review of the accuracy in diagnosing herniated discs. Spine 2000;25:1140-7.
- Daniëlle AWM van der Windt,Emmanuel Simons, Ingrid I Riphagen,Carlo Ammendolia, Arianne P Verhagen,Mark Laslett,Walter Devillé,Rick A Deyo,Lex M Bouter,Henrica CW de Vet,Bert Aertgeerts ;Physical examination for lumbar radiculopathy due to disc herniation in patients with low-back pain;Diagnostic Test Accuracy Review;Published Online: 17 FEB 2010;Assessed as up-to-date: 28 OCT 2008fckLRDOI: 10.1002/14651858.CD007431.pub2